Reliability of Weld Microstructure Property Calculations Comfort A

Reliability of Weld Microstructure & Property Calculations Comfort A. Adams Lecture, 2004

Are experiments necessary when designing welding alloys?

Fe Ru Os Hs 6 d 2 s

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Variables • • • C, Mn, Si, Ni, Cr, Mo, V, Co, B, N, O…. . Thermomechanical processing of steel Welding consumable Welding parameters Subsequent heat treatment

100 µm

Barrite, 1982 20 µm

Manual Metal Arc Weld 180 Amps 34 Volts 4 mm/s 200 °C interpass

calculations 800 2 1 3 Temperature / C 700 4 5 6 600 500 1. Fe-0. 4 C 2. Fe-0. 4 C-2 Si 3. Fe-0. 4 C-1 Ni 4. Fe-0. 4 C-1 Mn 5. Fe-0. 4 C-1 Mn-1 Cr 6. Fe-0. 4 C-2 Mn 400 300 200 0 10 10 1 10 2 3 10 Time / s 4 10 10 5

Barrite, 1982

Barrite, 1982 5 µm

Fe-1 Mn-C wt % manual metal arc welds 1. 0 Volume fraction 0. 8 Allotriomorphic 0. 6 Widmanstatten 0. 4 0. 2 0. 03 Acicular 0. 05 0. 07 Carbon / wt % 0. 09 0. 11

Bhadeshia & Svensson

Young & Bhadeshia, 1994

Bhadeshia & Svensson

Charpy fatigue tensile critical stress intensity corrosion

non-linear functions

y A B x

Cole & Bhadeshia, 1999

Cool, 1996

Cool, 1996

As-welded 600 °C 700 °C 650 °C Cool, 1996

Weld Shape - Spot Weld Power = 1. 0 k. W Walsh et al. 2002 Power = 2. 5 k. W Power = 1. 4 k. W 2 mm 0. 15 s 0. 65 s 0. 165 s 1. 15 s 0. 18 s 1. 65 s 0. 195 s 2. 15 s 0. 21 s 2. 65 s 0. 225 s 1. 65 s 0. 15 s

Walsh et al. 2002

Weld Shape - Stitch Weld at 2. 26 k. W Laser Output Laser beam Fusion Zone Laser beam Keyhole Walsh et al. 2002

SPOT WELD 38. 3 J/mm; 1 k. J 2. 15 s; 325 HV STITCH WELD 39. 4 J/mm; 1. 4 k. J 10 mm/s; 165 HV 50 mm

Are experiments necessary when designing welding alloys?

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